CN113440324B - Stent Delivery System - Google Patents

Abstract

The invention relates to a stent conveying system, which comprises a stent and a stent conveyor, wherein the stent conveyor comprises a sheath core tube, an outer sheath tube and an assembly part, the outer sheath tube is sleeved on the sheath core tube in an axially slidable manner, a containing cavity for containing the stent is formed between the inner wall of the outer sheath tube and the outer wall of the sheath core tube, the assembly part is provided with a fixed end and a free end opposite to the fixed end, the fixed end is connected with the sheath core tube, and when the stent is radially pressed on the sheath core tube, the free end and the stent are hooked to limit the stent. The bracket conveying system can improve the assembly precision.

Description

Stent Delivery System

technical field

The invention relates to the field of medical devices, in particular to a stent delivery system.

Background technique

This section provides background information related to the present disclosure only and is not necessarily prior art.

Interventional therapy has the characteristics of less trauma and fewer complications. At present, the treatment of cardiovascular diseases through interventional therapy has become a commonly used treatment method. With the continuous development of interventional technology and the improvement of interventional therapy technology, the advantages of using interventional technology to treat cardiovascular diseases such as aneurysm, arterial dissection disease, and vascular stenosis are becoming more and more prominent. In interventional technology, stent is a common device. Classified by structure, stents are mainly divided into two categories, one is covered stents, which are mainly composed of a membrane and a metal stent supporting the membrane. The covering membrane is generally made of biocompatible materials such as polyester and expanded polytetrafluoroethylene (e-PTFE) membrane, and the metal stent is generally made of materials such as nickel-titanium alloy or stainless steel. The other type is a bare stent, which does not contain a coating and is generally composed of a metal stent, such as a stainless steel stent or a nickel-titanium alloy stent. Among them, the metal stent in the covered stent and the bare stent can be classified into two types according to the preparation method: braided metal stent and cut metal stent. The raw material of the braided metal stent is generally a metal wire, which is formed by weaving and heat setting Metal stent; the raw material of cutting metal stent is generally pipe, which is made into cutting metal stent through cutting and heat setting.

Whether it is a covered stent or a bare stent, interventional therapy generally pre-assembles the stent in the sheath of the delivery system. During the operation, the delivery system delivers the stent to the lesion and releases the stent. The stent expands and closes to the vessel wall to isolate Blood flow and aneurysm and arterial dissection, or reopen the narrowed blood vessel channel, so as to re-establish the channel of normal blood circulation, and realize the interventional treatment of aneurysm, arterial dissection or vascular stenosis and other lesions.

With the widespread application of stent interventional technology, more and more clinical problems need to be optimized. Among them, the stent cannot be released, the stent release form is distorted, and the stent is damaged. The failure of the stent to be released leads to the inability to achieve interventional therapy. The distorted shape of the stent after release may lead to poor positioning of the stent, and damage to the stent may lead to insufficient radial support, which will affect the curative effect. In order to solve these problems, at present, many studies focus on the release mechanism, while ignoring the influence of assembly accuracy on whether the stent can be released accurately. The optimization of the release mechanism is conducive to improving the release accuracy, and the assembly accuracy also plays a vital role in the release accuracy. During the process of assembling the stent to the sheath, stacking or torsion of the stent will have an adverse effect on the release accuracy of the stent, and in severe cases may cause serious consequences that the stent cannot be released.

At present, there are mainly two ways to assemble the stent. One is to apply a radial force to the stent so that the stent is crimped on the sheath core tube, and then the stent and the sheath core tube are pushed into the sheath tube together. In this assembly method, the stent is also subjected to an axial push force while being subjected to radial compression force, and the thrust force of the axial force pushes the stent and the sheath core tube together into the sheath tube. If the stent and the sheath core tube are The relative sliding between them will lead to the phenomenon of stacking, and the stacking will affect the assembly accuracy of the bracket. The stacking caused by assembly generally includes the following three situations: 1) stacking at or near the proximal end, this is because at the initial stage of assembly, when the relative sliding occurs between the stent and the sheath core tube, the axis of the stent and the sheath core tube The axial displacement is not completely synchronized. When the axial displacement of the stent is greater than the axial displacement of the sheath core tube, the proximal part of the stent has entered the sheath tube, while the corresponding sheath core tube part is still outside the sheath tube. , with the continuous axial pushing force, the part of the stent that has been loaded into the sheath begins to move in the proximal direction, and finally coil stacking occurs at or near the proximal end. 2) Stacked in the middle of the stent, in the middle of the assembly, the stent and the sheath core tube slide relative to each other, resulting in that when the stent is pushed into the sheath tube, the corresponding sheath core tube is not completely pushed into the sheath tube, and has been assembled at this time The stent part in the sheath tube and the sheath core tube part did not move relative to each other, and with the continuous axial pushing force, the middle part of the stent was stacked. 3) Stacked at or near the far end, this is because during the initial assembly process, the stent and the sheath core tube slide relative to each other, so that the axial displacement of the stent toward the sheath tube is less than the corresponding axial displacement of the sheath core As a result, after the sheath core tube is pushed into the sheath tube, the corresponding bracket part is still located outside the sheath tube, resulting in relatively more parts that are not put into the sheath tube at the end of sheathing, so continuing to assemble Can result in stent stacking at or near the distal end.

In addition, because different implantation sites have different performance requirements for stents, in design, many stents have different wave heights, wave angles and/or metal amounts along the circumference, so when the stent is subjected to radial compression force, the stent Different from the reaction force opposite to the radial compressive force generated by each part along the circumferential direction, the reaction force generated by each part distributed along the circumferential direction is not necessarily evenly distributed along the circumferential direction. Some waveforms produce small reaction force, while others have large reaction force. The compression amount of the wave form with small reaction force is obviously greater than that of the wave form with large reaction force, and the wave form with large reaction force squeezes the waveform with small reaction force to one side. During the assembly process, the compression uniformity of the stent before entering the sheath can be artificially controlled and adjusted, but after entering the sheath, the tendency of the stent to return to its circumferential uneven distribution is unavoidable. The waveform is shifted, ie twisted, relative to the phase before it was pushed into the sheath. In addition, during the process of pushing the stent together with the sheath core tube into the sheath tube, the stent may also be twisted due to the circumferential displacement of the stent relative to the sheath core tube, which will cause the stent to appear distorted after being assembled into the sheath tube, Therefore, when the stent is implanted and released, it will also appear twisted. When the distortion is severe, it may even cause the bracket to be damaged.

Another way to assemble the stent is to hold the stent radially on the sheath core tube, keep the stent and the sheath core tube stationary, and then give the sheath tube a push force to move the sheath tube towards the stent and the sheath core tube to push the stent into place. and the sheath core tube are assembled into the lumen of the sheath tube. The risks of this assembly method are similar to those of the aforementioned method, and will not be repeated here.

Contents of the invention

Based on this, it is necessary to provide a stent delivery system capable of improving assembly accuracy.

A stent delivery system, comprising a stent and a stent delivery device, the stent delivery device including a sheath core tube, an outer sheath tube and an assembly, the outer sheath tube is slidably sleeved on the sheath core tube in the axial direction, And an accommodating cavity for accommodating the stent is formed between the inner wall of the outer sheath tube and the outer wall of the sheath core tube, and the fitting has a fixed end and a free end opposite to the fixed end, so The fixed end is connected to the sheath core tube, and when the stent is pressed radially on the sheath core tube, the free end is hooked with the stent to limit the position of the stent.

The sheath core tube of the stent delivery system is provided with an assembly with a free end. When the stent is pressed radially on the sheath core tube, the free end of the assembly is hooked to the stent to limit the position of the stent. Therefore, during the assembly process, the stent stacking phenomenon caused by relative sliding between the stent and the sheath core tube can be avoided, and thus, the stent delivery system can improve assembly accuracy.

Description of drawings

FIG. 1 is a schematic structural view of a stent delivery system according to an embodiment;

Fig. 2 is a schematic structural view of a stent transporter in an embodiment;

FIG. 3 is a partial schematic diagram of a stent delivery system in an assembled state according to an embodiment;

FIG. 4 is a partial schematic diagram of a stent delivery system in an assembled state according to another embodiment;

5a to 5d are schematic diagrams of the assembly process of the stent delivery system according to an embodiment;

6 is a partial schematic diagram of a stent delivery system in an assembled state according to another embodiment;

7 is a schematic diagram of a partial structure of a stent transporter in another embodiment;

Fig. 8 is a schematic structural view of an assembly of an embodiment;

Fig. 9 is a schematic diagram of a bending state of a stent transporter according to an embodiment;

Fig. 10 is a schematic structural view of an assembly in another embodiment;

Fig. 11 is a schematic structural view of an assembly in another embodiment;

Fig. 12 is a schematic structural view of an assembly in another embodiment;

Fig. 13 is a schematic structural view of an assembly in another embodiment;

Fig. 14 is a schematic structural view of an assembly in another embodiment;

Fig. 15 is a schematic structural view of an assembly in another embodiment;

Fig. 16 is a partial schematic view of a stent delivery system in another embodiment in an assembled state; Fig. 17 is a schematic structural view of a stent in an embodiment;

Fig. 18 is a schematic diagram of the bracket shown in Fig. 17 in an assembled state;

Fig. 19 is a schematic diagram of the size of an assembly and an outer sheath in an embodiment;

Fig. 20 is a schematic structural view of an assembly in another embodiment;

Fig. 21 is a schematic structural view of a stent in another embodiment;

Fig. 22 is a schematic diagram of a screenshot along the line II-II of Fig. 21;

23 and 24 are schematic diagrams of a cross-section of a stent in a compressed state according to an embodiment;

Fig. 25 is a schematic diagram of a braided form of a stent according to an embodiment;

Fig. 26 is a schematic structural view of the covering film of a stent according to an embodiment;

Fig. 27 is a schematic structural view of the coating of a stent according to an embodiment;

Fig. 28 is a schematic structural view of the covering film of a stent according to an embodiment;

Fig. 29 is a schematic structural view of a stent in another embodiment;

30a to 30e are schematic diagrams of the release process of the stent delivery system according to an embodiment;

Fig. 31 is a schematic structural view of an assembly assembly in an embodiment;

Fig. 32 is a schematic structural view of an assembly assembly in another embodiment;

Fig. 33 is a schematic structural view of an assembly assembly in another embodiment.

Detailed ways

In order to make the above objects, features and advantages of the present invention more comprehensible, specific implementations of the present invention will be described in detail below in conjunction with the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described here, and those skilled in the art can make similar improvements without departing from the connotation of the present invention, so the present invention is not limited by the specific implementations disclosed below.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of the invention. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention.

In the field of interventional medical devices, the "distal end" is defined as the end away from the operator during the operation, and the "proximal end" is defined as the end close to the operator during the operation. "Axial" refers to the direction parallel to the line connecting the center of the distal end and the center of the proximal end of the medical device, and "radial" refers to the direction perpendicular to the aforementioned axial direction.

Referring to FIG. 1 , a stent delivery system 100 according to an embodiment includes a stent delivery device 110 and a stent 120 .

Referring to FIG. 2 , the stent delivery device 110 includes a guide head 111 , a sheath core tube 112 , an outer sheath tube 113 , a fixed handle 114 and a movable handle 115 .

The guide head 111 is a hollow cavity structure with two ends open and a tapered distal end. The sheath core tube 112 is a hollow tube. The distal end of the sheath core tube 20 extends into the guide head 111 from the proximal open end of the guide head 111 and is fixedly connected with the guide head 111, and the cavity of the sheath core tube 112 communicates with the cavity of the guide head 111 to form a guide wire channel to ensure that the stent delivery device 110 can smoothly reach the lesion under the guidance of the guide wire.

Both the sheath core tube 112 and the outer sheath tube 113 are hollow tubular members. The outer sheath tube 113 is sheathed on the sheath core tube 112 and the outer sheath tube 113 and the sheath core tube 112 are coaxial. Moreover, the outer sheath tube 113 can slide axially relative to the sheath core tube 112 . As shown in FIG. 3 , when the outer sheath tube 113 slides axially until the distal end of the outer sheath tube 113 abuts against the guide head 111 or approaches the guide head 111, the outer sheath tube 113 and the sheath core tube 112 form a ring-shaped container. The housing cavity 116 , the bracket 120 is accommodated in the accommodating cavity 116 . Please compare Figure 2 and Figure 3, the fixed handle 114 and the sheath core tube 112 remain relatively fixed, the movable handle 115 is fixedly connected with the outer sheath tube 113, during the operation, hold the fixed handle 114 with one hand, and operate the movable handle 115 with the other hand, The outer sheath 113 is moved axially proximally, thereby releasing the stent 120 .

In one embodiment, as shown in FIG. 2 , the stent delivery device 110 further includes a support tube 117 sleeved on the proximal end of the sheath core tube 112 . The support tube 117 is coaxial with the sheath core tube 112 and fixedly connected. The outer sheath tube 113 is sheathed on the support tube 117 , and can slide axially along the support tube 117 to the sheath core tube 112 or along the sheath core tube 112 to the support tube 117 . The support tube 117 is set. On the one hand, the distal end of the support tube 117 can abut against the bracket 120 to play a position-limiting role; Good support to prevent the outer sheath tube 113 from bending.

Referring back to FIGS. 1 and 2 , the stent transporter 110 further includes an assembly 118 . The assembly part 118 is used to assist the assembly of the bracket 120 to improve assembly accuracy. The assembly part 118 is disposed on the outer wall of the sheath core tube 112 and fixedly connected with the sheath core tube 112 . The fitting 118 has a fixed end and a free end, one end connected to the sheath core tube 112 is a fixed end, and the other end opposite to the fixed end is a free end. In one embodiment, the fitting 118 is a protrusion disposed on the outer wall of the sheath core tube 112 , and the end of the fitting 118 away from the outer wall of the sheath core tube 112 is a free end. In one embodiment, the assembly part 118 is a cylindrical protrusion fixed on the outer wall of the sheath core tube 112 , one bottom surface of the cylindrical protrusion is a fixed end surface, and the other bottom surface is a free end surface. It can be understood that the shape of the assembly part 118 is not limited, for example, it may be an elliptical cylinder, a square cylinder and so on.

The stent 120 is a lumen structure. In one embodiment, the stent 120 is a stent graft. As shown in FIG. 1 , the stent 120 includes a support frame 121 and a membrane 122 covering the support frame 121 . The support frame 121 is a hollow lumen structure formed by weaving wires or cutting metal pipes, and the membrane 122 covers the support frame 121 in the circumferential direction to form a circumferentially closed lumen structure. The wires form a mesh of closed loops, eg, diamond mesh, square mesh, triangular mesh, circular mesh, and the like.

When assembling the stent 120 in the stent transporter 110 , firstly, the movable handle 115 is operated to axially displace the outer sheath tube 113 away from the sheath core tube 112 to expose the sheath core tube 112 . Next, the stent 120 is sheathed on the sheath core tube 112 from the end where the guide head 111 is located, and the stent 120 is compressed in the radial direction, and the stent 120 is crimped on the sheath core tube 112 . Take the closed-loop rhombus grid formed by the metal wires supporting the skeleton 121 as an example, when the support 120 is radially compressed, the rhombus grid of the support skeleton 121 still remains a closed-loop grid with four endpoints, and the assembly part 118 The free end stretches into the corresponding grid and hooks with the support 120 (the end face of the free end of the assembly part 118 protrudes from the support frame 121; or, is flush with the end face of the wire of the support frame 121; or, is lower than the support the end face of the metal wire of the frame 121, but still remains hooked with the bracket 120), the fitting 118 can restrict the movement of the bracket 120 along the axial and circumferential directions, so that the bracket 120 and the sheath core tube 112 remain relatively fixed, preventing both relatively sliding. As shown in Figure 1, the rhombus grid has four endpoints A, B, C and D (D point is not shown in Figure 1), when the support 120 slides towards the direction of the guide head 111 relative to the sheath core tube 112, the assembly part 118 It will collide with point B on the rhombus grid, that is, the tendency of the stent 120 to slide relative to the sheath-core tube 112 toward the guide head 111 is restricted by the fitting 118 . Similarly, the fitting 118 can limit the tendency of the bracket 120 to slide away from the guide head 111 . When the bracket 120 tends to twist, it will touch the intersection point C or D, so the fitting 118 can limit the twisting tendency of the bracket 120 . Therefore, when the stent 120 is radially compressed and held on the sheath core tube 112, due to the limiting effect of the assembly part 118, the relative sliding between the stent 120 and the sheath core tube 112 is restricted, so that During the advancement of the lumen of the sheath tube 113 , the movements of the stent 120 and the sheath core tube 112 are consistent, which is beneficial to avoid stacking. At the same time, it is beneficial to prevent the bracket 120 from twisting.

As shown in FIG. 3 , when the stent 120 enters the outer sheath tube 113 , the assembly part 118 still passes through the rhombic grid of the stent 120 , so the limiting effect on the stent 120 can still be maintained. That is, when the stent 120 is subjected to an axial or circumferential force along the sheath-core tube 112 , the fitting 118 can well restrict the shape of the stent 120 to avoid its axial movement and circumferential rotation.

It can be understood that the bracket 120 has a certain length, and in order to ensure a better limiting effect, the number of assembly parts 118 is reasonably set according to the length of the bracket 120 . At the same time, the bracket 120 has a lumen structure, and in order to ensure a better position-limiting effect, the orientation of the free ends of the plurality of assembly parts 118 can also be rationally arranged. In the embodiment shown in FIG. 1 , the number of assembly parts 118 is two, and the two assembly parts 118 are arranged at intervals. Also, when the stent 120 is crimped on the sheath core tube 112 , one fitting 118 is located at the distal end of the stent 120 , and the other fitting 118 is located at the proximal end of the stent 120 . The radial extensions of the free ends of the two fittings 118 are opposite. The two fittings 118 can better limit the bracket 120, and because the two fittings 118 are respectively located at the distal end and the proximal end of the bracket 120, and are arranged at intervals, the fittings 118 do not significantly increase the rigidity of the sheath core tube 112 , so that the stent delivery device 110 can maintain the ability to pass through the curved lumen path.

In another embodiment, the extension directions of the free ends of the two fittings 118 may be the same, so as to ensure the limiting effect on the bracket 120 .

The extension direction of the free end of the fitting 118 is not parallel to the sheath-core tube 112 . In one embodiment, the fitting 118 is perpendicular to the longitudinal central axis I-I of the sheath core tube 112 , that is, the extending direction of the free end of the fitting 118 is perpendicular to the longitudinal central axis I-I, as shown in FIG. 3 .

In one embodiment, the assembly part 118 forms an acute angle with the longitudinal central axis I-I of the sheath core tube 112, that is, the extension direction of the free end of the assembly part 118 forms an acute angle with the longitudinal central axis I-I, and the assembly part 118 is inclined relative to the longitudinal central axis I-I, As shown in Figure 4.

It should be noted that no matter whether the assembly part 118 is perpendicular to the longitudinal central axis I-I or the assembly part 118 is inclined relative to the longitudinal central axis I-I, when the number of the assembly parts 118 is multiple, the position-limiting effect is ensured, so that the bracket 120 and the sheath On the premise that the core tube 112 remains relatively fixed, the arrangement of the plurality of assembly parts 118 on the sheath core tube 112 is not limited. For example, a plurality of fittings 118 may all be located on the same side of the longitudinal central axis I-I; or, some of the fittings 118 are located on the same side of the longitudinal central axis I-I, and another part of the fittings 118 are located on the other side of the longitudinal central axis I-I. The plurality of fittings 118 located on both sides of the longitudinal central axis I-I may be radially opposite or not, that is, they may be arranged symmetrically or asymmetrically along the longitudinal central axis I-I. Alternatively, the free ends of the plurality of fittings 118 are alternately located on both sides of the longitudinal central axis I-I of the sheath-core tube 112 .

Please refer to Fig. 5a, in one embodiment, there are multiple fittings 118, and the plurality of fittings 118 form an acute angle with the longitudinal central axis I-I of the sheath core tube 112, and the plurality of fittings 118 form a group of two, each The groups take the longitudinal central axis I-I of the sheath core tube 112 as the axis of symmetry, and are symmetrically arranged on both sides of the longitudinal central axis I-I, and the multi-assembly parts 118 are arranged at intervals along the axial direction of the sheath core tube 112 . And, in the multi-assembly fittings 118, some are inclined to the far end (meaning that the free end of the fitting 118 is closer to the far end than the fixed end), and some are inclined to the proximal end (the free end of the fitting 118 is closer to the fixed end than the fixed end). proximal). The distally angled multi-assembly assembly 118 is closer distally than the proximally angled multi-assembly assembly 118 . That is, from the distal end to the proximal end of the sheath core tube 112, the multi-assembly fittings 118 inclined to the distal end are arranged at intervals in the axial direction, and the multi-assembly fittings 118 inclined to the proximal end are arranged at intervals in the axial direction, and The set of distally angled fittings 118 on the most distal guide head 111 is located distal to all proximally angled fittings 118 . The multi-assembly parts 118 inclined to the distal end can be arranged at equal intervals or at unequal intervals. The multiple assembly parts 118 that are inclined toward the proximal end can be arranged at equal intervals, or at unequal intervals. When the assembly parts 118 with different inclination directions are all arranged at equal intervals, the interval between the multi-assembly parts 118 inclined toward the distal end and the interval between the multi-assembly parts 118 inclined toward the proximal end may be equal or different.

When the stent 120 and the sheath core tube 112 are to be moved axially toward the outer sheath tube 113, the thrust applied to the stent 120 and the sheath core tube 112 needs to be able to change the assembly part 118 from the state shown in FIG. Only when the orientation of fitting 118 changes, the metal wire of stent 120 can continue to press fitting 118 in Fig. 5c, so that a gap is created between fitting 118 and the inner wall of outer sheath tube 113, thereby causing fitting 118 to slip out of the gap, and the outer sheath The inner cavity of the tube 113 cannot produce a limiting effect, thereby causing the stent 120 to shift or twist. Compared with the vertically arranged fittings 118, the facing fittings 118 will only slip out under a greater force. Therefore, this kind of fittings 118 inclined toward the direction away from the guide head 111 can effectively prevent the bracket 120 from approaching The direction of the guide head 111 slips to cause the assembly part 118 to slip off.

After the bracket 120 is partially loaded into the outer sheath tube 113, the bracket 120 and the sheath core tube 112 have been kept relatively fixed at the proximal end, and the outer sheath tube 113 is continued to be pushed in the direction close to the guide head 111, and a plurality of assembly parts inclined to the distal end 118 can become more inclined according to the outer sheath 113, so as to enter into the outer sheath 113 more conveniently.

By arranging the assembly parts 118 with different orientations and reasonably distributing them on the sheath core tube 112 , the stent 120 is provided with a limiting effect and at the same time, the assembly is facilitated.

In one embodiment, the multi-assembly fittings 118 inclined toward the distal end and the multi-assembly fittings 118 inclined toward the proximal end are arranged at unequal intervals, and the distance between the multi-assembly fittings 118 inclined toward the distal end is relatively small near the distal direction. , near the proximal direction, the intervals of the proximally inclined multiple assembly parts 118 are smaller. At the beginning of assembly, it is most likely that the bracket 120 and the sheath core tube 112 will slide relative to each other. Therefore, the interval between the multi-assembly parts 118 that are inclined to the proximal end is relatively small, and the number of multi-assembly parts 118 that are inclined to the proximal end is more. , so as to avoid the situation that the stent 120 is stacked at or near the proximal end at the beginning of assembly, and the part of the stent 120 that enters the outer sheath 113 is anchored, and it is also beneficial to maintain the stent 120 and the sheath as a whole The relative fixation of the core tube 112 is beneficial to slowing down or avoiding the phenomenon of middle stacking or distal stacking that may occur later.

As shown in Fig. 6, in one embodiment, there are a plurality of assembly parts 118, and the plurality of assembly parts 118 form a group of two, and each group takes the longitudinal center axis I-I of the sheath core tube 112 as the axis of symmetry, and is symmetrically arranged on On both sides of the longitudinal central axis I-I, multiple assembly parts 118 are arranged at intervals along the axial direction of the sheath-core tube 112 . Moreover, among the multi-assembly fittings 118 , some are inclined to the distal end, some are inclined to the proximal end, and some are perpendicular to the longitudinal central axis I-I of the sheath-core tube 112 . And, the far-end inclined fittings 118 (one or more groups) are located at the distal end, and the proximally inclined fittings 118 (one or more groups) are positioned at the proximal end, with the longitudinal central axis I-I of the sheath core tube 112 Vertical fittings 118 (one or more sets) are located in the middle. Such setting can also improve the assembly accuracy.

Please refer to FIG. 7 and FIG. 8 together. In another embodiment, the assembly part 118 includes a base 1181 and a protrusion 1182 disposed on the base 1181 . The base 1181 and the protrusion 1182 are integrated. Alternatively, the base 1181 and the protrusion 1182 are fixedly connected by welding, gluing and the like. The materials of the base 1181 and the protrusion 1182 can be the same or different. The base 1181 is fixedly disposed on the outer wall of the sheath core tube 112 , and the base 1181 is a fixed end of the fitting 118 . The protrusion 1182 extends from the connection portion with the base 1181 , and the end of the protrusion 1182 away from the base 1181 is a free end.

In one embodiment, as shown in FIG. 8 , the base 1181 is a hollow structure, and the middle part of the base 1181 has an inner cavity, and the base 1181 is sheathed on the sheath-core tube 112 through the inner cavity. The protrusion 1182 is fixed on the outer wall of the base 1181 . The fixing method of the assembly part 118 including the base 1181 to the sheath core tube 112 is easier and more reliable. The base 1181 can reduce the difficulty of the manufacturing process. For the assembly part 118 not including the base 1181 , due to the relatively small size of the assembly part 118 , a very precise operation is required to complete the fixing of the assembly part 118 and the sheath core tube 112 . If the sheath core tube 112 and the fittings 118 are integrally formed by mold molding, the number of the fittings 118 and the arrangement of the fittings 118 on the sheath core tube 112 may be different for different specifications or different types of stents 120 , therefore, For different products, it may be necessary to open the mold again and again, which will inevitably increase the cost and the difficulty of control.

Therefore, the assembly part 118 including the base 1181 and the protrusion 1182 reduces the manufacturing process difficulty and helps to reduce the manufacturing cost. The spacing of the plurality of assembly parts 118 can be flexibly set as required. Even if the base 1181 is added, a plurality of fittings 118 are still arranged at intervals on the sheath core tube 112 , which does not significantly increase the rigidity of the sheath core tube 112 . On the premise of satisfying reliable fixation and not significantly increasing the difficulty of the process, the axial length of the base 1181 should be as small as possible, so as to minimize the impact on the rigidity of the sheath core tube 112 . Moreover, for the outer sheath 113, clinically, it is generally desired that the radial dimension of the outer sheath 113 is as small as possible. In order not to significantly occupy the inner space of the outer sheath 113, the base 1181 has sufficient strength so that Under the premise that the assembly part 118 is reliably connected with the sheath core tube 112, the thickness of the base 1181 should be as small as possible. In one embodiment, when the base 1181 is a hollow cylinder, the ratio of the axial length of the base 1181 to the axial length of the protrusion 1182 is 1:1-1:25, and the outer diameter of the sheath-core tube 112 d3, the outer diameter of the base 1181 is d4, d3+0.2mm≤d4≤d3+4mm.

In one embodiment, each fitting 118 includes only one protrusion 1182 . Moreover, when multiple fittings 118 are provided on the sheath core tube 112, the orientations of the protrusions 1182 may be the same or different. For example, as shown in FIG. 7 , the protrusions 1182 are oriented differently in the plurality of assemblies 118 . Since the stent 120 has a lumen structure, the stent 120 is sheathed on the sheath core tube 112 , and the protrusions 1182 have different orientations, which can limit multiple positions from the circumferential direction, which is beneficial to prevent the stent 120 from twisting relative to the sheath core tube 112 . The plurality of assembly parts 118 can be arranged regularly or irregularly. For example, a plurality of assembly parts 118 are regularly arranged on the sheath-core tube 112 with a phase shift. Staggering a phase means that in the cross-sectional view of the sheath core tube 112, the protrusions 1181 of the plurality of fittings 118 are distributed along the circumferential direction, and any two adjacent protrusions 1182 are spaced apart from each other in the circumferential direction equal.

In another embodiment, as shown in FIG. 9 , a plurality of fittings 118 are arranged on the sheath core tube 112 at intervals, and each fitting 118 only includes one protrusion 1182 , and the protrusions 1182 of the plurality of fittings 118 The orientations are consistent, that is, the protrusions 1182 of the plurality of assembly parts 118 are located on the same side of the longitudinal central axis I-I (not shown in FIG. 9 ). Moreover, the protrusion 1182 faces the greater curvature side E1 of the outer sheath 113 . When the stent delivery system 100 passes through a curved lumen path (for example, a curved blood vessel), the outer sheath 113 and the stent 120 located therein will bend accordingly to form a large curvature side E1 and a small curvature side E2. At E2, the wires of the stent 120 will gather, while at the greater curvature side E1, the wires become sparse and the risk of displacement increases. Orienting the protrusion 1182 of the assembly part 118 toward the large bending side E1 can better limit the position of the metal wire of the bracket 120 located on the big bending side E1 and avoid the displacement of the bracket 120 . Moreover, setting the protrusion 1182 toward the greater curvature side E1 facilitates the stent delivery system 100 to pass through the curved lumen path.

Referring to FIG. 10 , FIG. 11 and FIG. 12 , in another embodiment, each assembly part 118 includes a plurality of protrusions 1182 , and the plurality of protrusions 1182 are arranged at intervals along the circumference of the base 1181 . Alternatively, the plurality of protrusions 1182 are divided into two groups, and the two groups of protrusions 1182 are arranged at intervals in the axial direction, and each group of protrusions 1182 is arranged at intervals in the circumferential direction. A plurality of protrusions 1182 are arranged at intervals along the circumferential direction of the base 1181 to maintain a more balanced position-limiting performance in the circumferential direction.

In one embodiment, the base 1181 of the assembly part 118 is a hollow cylinder. On the one hand, the processing is more convenient; on the other hand, the connection between the assembly part 118 and the sheath core tube 112 is relatively reliable. It can be understood that, in other embodiments, the shape of the base 1181 is not limited to a hollow cylinder, and any shape capable of fixing the assembly part 118 on the sheath-core tube 112 is acceptable. For example, as shown in Figure 13, the base 1181 is an arc-shaped shell, the shape of the surface of the arc-shaped shell away from the protrusion 1182 is adapted to the arc-shaped surface of the sheath core tube 112, and the arc-shaped shell is attached to the On the outer wall of the sheath core tube 112 , it is beneficial for the assembly part 118 to be reliably fixed on the surface of the sheath core tube 112 . Moreover, since the base 1181 does not completely cover the sheath core tube 112 in the circumferential direction, it is beneficial to avoid significantly increasing the rigidity of the sheath core tube 112 , so that the sheath core tube 112 maintains a certain degree of flexibility to facilitate the curved lumen path. In one embodiment, the ratio of the axial length of the arc-shaped housing to the axial length of the protrusion 1182 is 1:1-1:25, and the thickness of the arc-shaped housing is 0.1-4mm.

In another embodiment, please refer to FIG. 14 and FIG. 15 , the base 1181 is hollow in the shape of a truncated cone, the outer contour is in the shape of a truncated cone, and the inner cavity is in the shape of a cylinder. It should be noted that no matter how the shape of the base 1181 changes, the number of protrusions 1182 of each assembly part 118 is not limited, and may be one or more.

When the base 1181 is a hollow circular truncated shape, the orientation of the base 1181 is not limited. As shown in FIG. 16 , in one embodiment, the large end of some bases 1181 is located at the proximal end, and the large end of some bases 1181 is located at the distal end, and the orientations of the corresponding protrusions 1182 are also different.

No matter what kind of structure the assembly part 118 is, such as only including the columnar protrusion structure or the structure including the base 1181 and the protrusion 1182, in one embodiment, the end surface of the free end of the assembly part 118 is a spherical surface, which is beneficial to reduce the number of assembly parts 118. The scratching of the inner wall of the outer sheath tube 113 avoids damage to the inner wall of the outer sheath tube 113 .

An assembly 118 is fixed on the outer wall of the sheath core tube 112 of the stent transporter 110. During the assembly process, the free end of the assembly 118 extends into the metal grid of the stent 120, and hooks with the stent 120, resulting in a limited Positioning effect, avoiding the relative sliding of the stent 120 and the sheath core tube 112, so that the stent 120 and the sheath core tube 112 remain relatively fixed, so that when the stent 120 and the sheath core tube 112 are pushed into the outer sheath tube 113 together, the stent 120 and the sheath core tube 112 The axial displacement of the sheath core tube 112 can be kept consistent, which is beneficial to avoid the phenomenon of stacking. Moreover, after the stent 120 and the sheath core tube 112 are assembled in the outer sheath tube 113 , the assembly part 118 still maintains a limiting effect on the stent 120 , preventing the stent 120 from twisting in the lumen of the outer sheath tube 113 . Therefore, the assembly accuracy of the stent transporter 110 is relatively high.

It should be noted that the metal wires of the stent 120 in the above embodiment form a closed-loop grid, and the position-limiting effect is realized by passing the assembly part 118 through the closed-loop grid. In another embodiment, whether the support frame 121 is prepared by weaving or cutting, the metal wires of the support frame 121 do not form a closed-loop grid. As shown in FIG. 17 , the support frame 121 is a Z-shaped wave structure or a sinusoidal wave structure.

For the stent 120 in which the metal wires do not form a closed-loop grid, the above-mentioned stent transporter 110 can also improve the assembly accuracy. FIG. 18 is a schematic diagram of a state in which the stent 120 of the Z-shaped wave structure is assembled in the outer sheath tube 113 , and the assembly part 118 is kept hooked to the wire of the stent 120 . Specifically, the assembly part 118 is hooked with the small curved side of the crest or trough of the Z-shaped wave, so that the bracket 120 can be limited in the axial and circumferential directions, thus avoiding the stacking of the bracket 120 in the outer sheath during the assembly process. The phenomenon of torsion inside the tube 113.

In one embodiment, regardless of whether the support frame 121 is prepared by weaving or cutting, and regardless of whether the metal of the support frame 121 is a closed-loop grid or a non-closed-loop Z-shaped wave, sine wave and other structures, the stent 120 does not include a coating 122 , that is, the stent 120 is a bare stent. For the stent 120 that does not include the covering film 122, the limiting effect of the assembly part 118 is better. As for the stent including the covering film 122 , by reasonably matching the assembly part 118 , the outer sheath tube 113 and the covering film 112 , the effect of improving the assembly accuracy can also be achieved.

The fitting 118 should be able to be hooked with the stent 120 and fit into the outer sheath 113 without damaging the stent 120 and the outer sheath 113 .

During the assembly process, when the bracket 120 is crimped on the sheath core tube 112 , the fittings 118 protrude into the rhombus grid of the bracket 120 , or the fittings 118 hook with the crests or troughs of the bracket 120 . And, after the stent 120 enters the outer sheath tube 113, the assembly part 118 still maintains the state of extending into the rhombus grid, or stretches out from the crest or trough, so as to ensure the position-limiting effect and keep the stent 120 in the outer sheath tube 113. in the form. Therefore, the fitting 118 should have a certain height h1 (as shown in FIG. 19 , the height is defined as the distance from the free end of the fitting 118 to the longitudinal central axis I-I of the sheath core tube 112 ). When h1 is so small that it is difficult for the assembly part 118 to hook the bracket 120, it is difficult to form a limiting effect; The fittings 118 may scrape against the inner wall of the outer sheath 113 , on the one hand, it will cause assembly difficulties, and on the other hand, the protruding fittings 118 may damage the inner wall of the sheath.

In one embodiment, when the assembly part 118 has a certain degree of elasticity, so that the assembly part 118 can be properly squeezed in the radial direction, the size of h1 can be appropriately increased, so that the assembly part 118 can be reliably hooked to the bracket 120 , effectively prevent the stent 120 and the sheath core tube 112 from sliding relative to each other, and when the stent 120 is assembled into the outer sheath tube 113, the assembly part 118 can properly elastically abut against the inner wall of the outer sheath tube 113, effectively preventing the stent 120 from moving. bit. At the same time, when the stent 120 includes the coating 122 , the assembly part 118 has certain elasticity or the hardness of the assembly part 118 is small, which is beneficial to avoid damage to the coating 122 . Therefore, in one embodiment, when the inner diameter of the outer sheath tube 113 is d1, and the hardness of the assembly part 118 is 25D to 85D, 0.5d1<h1<0.8d1, so as to ensure that the free end of the assembly part 118 can extend to the bracket 120 outside, so as to be reliably hooked with the bracket 120 without causing damage to the covering film 122 .

For the bracket 120 comprising the covering film 122, the assembly part 118 will be against the covering film 122 after stretching out from the rhombic grid of the support 120. When the height h1 of the assembly part 118 is too large, the free end of the assembly part 118 is easy to The coating 122 is damaged. Therefore, the height h1 of the assembly part 118 should be integrated with the inner diameter d1 of the outer sheath tube 113, the wire diameter d2 of the metal wire of the stent 120 (when the support frame 121 is formed by cutting, d2 is the wall thickness of the support frame 121) and the coating The thickness t of 122 is reasonably selected to ensure reliable positioning, avoid twisting of the stent 120 in the outer sheath 113 and avoid damage to the covering membrane 122 . In one embodiment, 0.35×d1−2×d2−t≤h1≤0.85×d1, so as to combine the above three effects.

In one embodiment, for the stent 120 including the membrane 122 , 0.35×d1−2×d2−t≦h1≦0.7×d1.

In one embodiment, for the stent 120 without the membrane 122 , h1 may be appropriately increased to improve the effect of limiting the position of the stent 200 . Especially for the bare stent formed by braiding, the braided wire is relatively smooth, so it is more likely to be displaced during the assembly process, so the size of h1 should be appropriately increased, but it should not be too large to resist the outer sheath tube 113 . At the same time, if h1 is too small, the assembly part 118 is likely to slip off from the wire and it is difficult to play a position-limiting role. Therefore, in one embodiment, 0.4×d1−2×d2≦h1≦0.85×d1, so as to better balance the effects of position limitation and avoiding damage to the outer sheath tube 113 . In one embodiment, 0.45×d1−0.5mm≤h1≤0.55×d1+0.5mm, so as to better balance the effect of limiting the position and avoiding damage to the outer sheath tube 113 .

Regardless of whether the metal wire weaves to form a closed-loop grid or a non-closed-loop Z-shaped wave, sine wave and other structures, or the metal tube is cut to form a closed-loop grid or a non-closed-loop structure, the size of the closed-loop grid and the non-closed-loop Z The corresponding radii of the crests or troughs of type waves, sine waves, etc. should be within a certain range, and when the bracket 120 is compressed, the size of the mesh and the size of the crests or troughs will be correspondingly reduced, so the assembly part 118 and The size of the cross-sectional area of the contact part of the grid, wave crest or trough should be reasonable. On the one hand, the cross-sectional area should not be too large, so that the assembly part 118 can be hooked with the bracket 120 to provide a limiting effect; on the other hand , the cross-sectional area should not be too small, so as to ensure that the assembly part 118 has sufficient strength to provide a limiting effect, and at the same time, prevent the assembly part 118 from breaking from the root.

In one embodiment, the cross-sectional area of the fitting 118 (the area of the section parallel to the longitudinal central axis I-I of the sheath-core tube 112) is S1 (when the fitting 118 is a columnar structure, S1 is the cross-sectional area of the columnar structure; When the assembly part 118 includes the base 1181 and the protrusion 1182, S1 is the cross-sectional area of the protrusion 1182), when the metal wire of the support 120 forms a closed-loop grid, and in the natural unfolded state, the grid area of the support 120 is S2, then 0.001×S2≦S1≦0.2×S2, so as to give consideration to both the strength of the assembly part 118 and the limiting effect of the assembly part 118 on the bracket 120 .

In one embodiment, 0.002×S2≦S1≦0.08×S2.

In one embodiment, when the outer diameter of the outer sheath tube 113 is less than or equal to 14F, 0.03mm ² ≤ S1 ≤ 1.8mm ² . In another embodiment, 0.07 mm ² ≤ S1 ≤ 0.8 ^{mm 2} .

When the metal wire of the support 120 forms a non-closed-loop structure, for example, the support frame 121 includes a plurality of wave-shaped ring structures containing crests and troughs, in order to realize the position-limiting effect, the assembly part 118 should be able to form with the crests or troughs of the support 120. The hook, ie fitting 118, should be able to penetrate the bend of the wire. The radius of the bending part of the metal wire is R1, in one embodiment, 0.05×R1×R1×π≤S1≤R1×R1×π, so as to give consideration to the strength of the assembly part 118 and the limiting effect of the assembly part 118 on the bracket 120 .

In one embodiment, in order to take into account the strength of the assembly part 118 and avoid damage to the outer sheath 113, when the assembly part 118 is a columnar structure, as shown in Figure 20, the assembly part 118 includes a rigid part 1183 and a flexible part 1184, wherein the rigid part 1183 is a fixed end, fixedly connected with the sheath core tube 112, one end of the flexible part 1184 is connected with an end of the rigid part 1183 away from the sheath core tube 112, and the other end is a free end. When the bracket 120 is pressed onto the sheath core tube 112 , the fitting 118 is hooked to the bracket 120 , and the free end of the flexible portion 1184 is against the coating 122 , which is beneficial to avoid damage to the coating 122 . In order to ensure that the entire assembly part 118 has sufficient strength to realize the position-limiting function during the assembly process, the hardness ratio of the rigid part 1183 and the flexible part 1184 is 0.3-0.9, and the length ratio is 1:5-5:1.

In one embodiment, when the fitting 118 includes the base 1181 and the protrusion 1182, the protrusion 1182 includes a rigid part and a flexible part, the ratio of the hardness of the rigid part to the flexible part is 0.3-0.9, and the ratio of the length is 1: 5～5:1.

In existing studies, in order to keep the stent 120 and the sheath core tube 112 relatively fixed, friction elements are usually provided on the surface of the sheath core tube 112 to prevent the stent 120 and the sheath core tube 112 from sliding relative to each other through surface friction. Increasing the surface friction can keep the bracket 120 and the sheath core tube 112 relatively fixed to a certain extent, but the limiting effect of this method is limited, and it is difficult to achieve a reliable limiting effect. During the process, the stent 120 and the sheath core tube 112 still have a certain degree of relative sliding, resulting in the phenomenon of stacking. Moreover, the way of limiting the position by surface friction often needs to increase the surface area of the friction element, that is, the larger the area of the friction element covering the surface of the sheath core tube 112, the better. In this way, the rigidity of the sheath core tube 112 will be increased, thereby reducing the support. The compliance of the delivery device 110 increases the difficulty for the stent delivery device 110 to navigate the tortuous lumen path. The stent delivery device 110 of the present disclosure does not significantly increase the rigidity of the sheath core tube 112 by disposing discontinuously distributed fittings 118 on the sheath core tube 112 , and thus does not significantly reduce the flexibility of the stent delivery device 110 . Moreover, the assembly part 118 provides a limiting effect by hooking with the bracket 120 , and this limiting effect is more reliable than the frictional effect. However, for the stent 120 including the covering film 122, since there is a possibility that the protruding fitting 118 may break and damage the covering film 122, no one has set the fitting 118 to limit the position of the stent 120 during the assembly process. . However, the present disclosure can avoid damage to the coating 122 while ensuring the position-limiting effect by reasonably setting the size of the assembly part 118 and the performance of the coating 122 .

The material of the covering film 122 can be plastic, dacron or polyester and the like. For example, the plastic can be polytetrafluoroethylene (PTFE), the polyester can be polyethylene terephthalate (PET) or polyurethane (PU), and so on. The reason why the covering film 122 is burst is that it is subjected to the radially outward force of the fitting 118 , and reducing the risk of the covering film 122 being burst by the fitting 118 can be considered comprehensively from two aspects. On the one hand, it is the performance and size of the assembly 118 itself, such as hardness, height h1 and cross-sectional area S1, etc.; on the other hand, it is the performance of the coating 122 itself.

Regarding the size of the assembly part 118 itself, the height h1 needs to be as small as possible on the premise that the assembly part 118 can hook the bracket 120 reliably, and the cross-sectional area S1 needs to be on the premise that the assembly part 118 can hook the bracket 120 reliably down as big as possible.

Regarding the performance of the covering film 122 itself, when the covering film 122 is subjected to a relatively large force of the assembly part 118, it can allow a certain extension without breaking. Therefore, the elongation of the coating 122 should meet certain requirements. If the elongation of the covering film 122 is too small, the free end of the fitting 118 may abut on the covering film 122, especially for a stent 120 with a smaller metal mesh, this possibility is higher, and the formation is formed entirely by compression. The folds of the covering film 122 cannot ensure that the assembly part 118 stretches into the grid of the wire, and the surface of the covering film 122 is relatively smooth. position, but can not achieve a good limit effect. However, when the elongation of the coating 122 is too large, under the action of the fitting 118, it is easy to cause the coating 122 to arch, thereby reducing the local thickness of the coating 122 and forming a weak part, which will increase the After the stent 120 is released, due to the effect of blood pressure, there is a risk of the weakened part being ruptured or blood penetrating the weak part.

Therefore, in one embodiment, 95%≦elongation≦300%.

The test method of elongation: cut the film-coated material into a sample with a length greater than 90mm and a width equal to 15mm, fix the sample on the fixture of the tensile machine, the distance between the two fixtures is 50mm, stretch the film slowly until the sample breaks, and record The maximum force F in this process and the stretched length L1 of the film at the time of the maximum force, then the elongation = (L1-50)/50*100%.

At the same time, the breaking strength of the covering film 122 will also have a certain influence. When the breaking strength of the covering film 122 is too small, the assembly part 118 is easy to break through the covering film 122 and cause the stent 120 to fail. However, the coating 122 with higher breaking strength generally has smaller porosity or larger thickness, the decrease of porosity will affect the effect of endothelial adhesion, and the increase of the thickness of the coating 122 will reduce the flexibility of the stent 120 .

Therefore, in one embodiment, 0.5 N/mm≦breaking strength≦15.0 N/mm. In another embodiment, 1.0 N/mm < breaking strength < 9.5 N/mm.

Wherein, the breaking strength of the coating material is obtained according to the test method of elongation above, breaking strength=F/15mm.

Moreover, the thickness t of the covering film 122 should satisfy a certain relationship with the height h1 of the assembly part 118 . When t is large and h1 is small, it is difficult for the assembly part 118 to lift up the coating 122 , and it cannot be ensured that the assembly part 118 and the metal wire of the bracket 120 are hooked reliably. When t is smaller, the coating 122 is thinner, and when h1 is larger, the risk of the coating 122 being burst is higher. Therefore, in one embodiment, 0.010≦t/h1≦0.500. In another embodiment, 0.013≤t/h1≤0.250.

The shape of the coating 122 itself also has a certain influence on avoiding damage caused by the assembly part 118 . Please refer to Fig. 21 and Fig. 22 together. In the natural state, the cross-sectional shape of the stent 120 is roughly circular, and when the stent 120 is radially compressed onto the sheath core tube 112, as shown in Fig. 23 and Fig. 24, the adjacent metal The film 122 between the wires is basically opened in an arc shape, forming a plurality of folds 1222. The folds 1222 provide a certain space for the fitting 118, and the free ends of the fitting 118 extend into the folds 1222, which is beneficial to avoid the The graft 122 is ruptured by the fitting 118 during the process and while the stent 120 is inside the outer sheath 113 . The stent 120 is compressed due to the radial compression force. The radial compression force actually acts on the support frame 121 of the stent 120. Under the action of the radial compression force, the support frame 121 will be pressed against the sheath core tube 112. In this state, if the coating 122 between the metal wires of the supporting frame 121 is in a tight state, the risk of the coating 122 being ruptured by the radially protruding fittings 118 is relatively low. high. Therefore, in the compressed state, the membrane 122 forms proper wrinkles 1222 to help reduce the risk of the membrane 122 being burst by the fitting 118 .

A suitable compression ratio can ensure that the covering film 122 between adjacent wires is in a wrinkled state. When the stent 120 is compressed, the distance between adjacent wires is shortened, and the membrane 122 forms wrinkles 1222 along with the compression process. Assuming that the diameter of the stent 120 in the natural state is D1, and the inner diameter of the outer sheath 113 is d1, the compression ratio of the stent 120 is defined as (D1-d1)/D1, and the larger the compression ratio, the more compressed the stent 120 is. big. The smaller the compressibility, the smaller the change in spacing between adjacent metal wires in any grid of the stent 120 from the natural state to the compressed state during assembly, the smaller the wrinkle degree formed by the coating 120, and the easier it is to be assembled. Accessory 118 is broken. In one embodiment, please return to FIG. 21 , the supporting frame 121 is composed of multiple rhombus grids, and any rhombus grid has four intersection points, a, b, c and d. Wherein, points b and d are distributed at intervals along the axial direction, and points a and c are distributed at intervals along the radial direction. It can be understood that, when the stent 120 is in a compressed state, the degree of wrinkling of the membrane 122 closer to the intersection point is smaller, the degree of wrinkling of the membrane 122 farther away from the intersection point is greater, and the degree of wrinkling at the center of the grid is maximum. Therefore, the membrane 122 closer to the intersection point is easier to be broken by the fitting 118 . Therefore, if the compressibility is too small, the risk of the part of the covering film 120 in the stent grid near the intersection point being ruptured by the assembly part 118 is significantly increased. It can be understood that although from a design point of view, the assembly part 118 should protrude from the center of the rhombus grid, but due to the precision of the production process and the axial push force received during assembly, the assembly part 118 may be biased closer to In the position of the intersection point, the actual damage of the covering film 122 often occurs near the intersection point, especially near points b and d.

However, if the compression rate is too large, when the stent 120 and the sheath core tube 112 are pushed into the outer sheath tube 113, there will not be enough space to accommodate the assembly part 118, and if the force is pushed, the outer sheath tube will be damaged even if the sheathing is successful. The local release force of 113 is large, which makes it difficult to release the bracket 120 .

Therefore, in one embodiment, 40%≦compression ratio≦85%. Within the range of the compression rate, the safety of the assembly process, the convenience of transportation and the convenience of release are taken into account.

When the covering film 122 is a double-layer structure, including an inner film and an outer film, and the support skeleton 121 is located between the inner film and the outer film, for the support skeleton 121 formed by weaving, the grid has four intersection points a , b, c, and d, when the assembly 118 is located near the intersection points a, b, c, and d and is subjected to a force in the direction of the intersection point, the crossed metal wires have the risk of sliding against each other, and the metal wires are affected near the intersection point Mutual movement due to force will cause the inner membrane and the outer membrane to separate, and even cause the stent 120 to fail in severe cases.

In one embodiment, as shown in FIG. 21 , the braiding manner of the supporting skeleton 121 of the bracket 120 is cross-hung. This intersecting and interlocking design can well prevent the metal wires near the crossing point from sliding against each other due to the action of the fitting 118 , resulting in the separation of the inner film and the outer film of the covering film 122 . In the embodiment shown in Fig. 21, each intersection is an interlocking design. In another embodiment, as shown in FIG. 25 , in the metal grid supporting the skeleton 121, only points b and d in the axial direction are intersected, and points a and c are common intersections, that is, only overlapping, No hangups happened. Because the bracket 120 is not subjected to additional circumferential external force during the assembly process, the risk of circumferential displacement is smaller than that of the axial direction. Therefore, only the intersecting intersections are formed in the axial direction, and the axial movement can be guaranteed first. The covering film 122 will not be damaged at the intersection. Moreover, the intersection points of the bracket 120 can be reduced as a whole, so that the bracket 120 has a certain degree of flexibility.

The cross-hung design, the metal wires are fixedly connected at the intersections, which can limit the displacement of the metal wires at the intersections to a certain extent. However, generally, when the covering film 122 is a single-layer structure, the covering film 122 is a monolithic structure. When the covering film 122 is a two-layer structure including an inner film and an outer film, the inner film and the outer film are respectively integral structures. The metal wire at the interhanging part can rotate around the hinge within a certain range, which may also cause the risk of separation or damage of the covering film 122 . Therefore, in one embodiment, the metal wires of the stent 120 only hang on each other at the intersection points in the axial direction. And, as shown in FIG. 26 , the coating 122 includes an inner film 1223 and an outer film 1224, wherein the inner film 1223 is a cylindrical integral structure, and the inner film 1223 is wrapped by the supporting frame 121 in the circumferential direction so that Form a circumferentially closed lumen structure. The outer film 1224 is a strip structure, and the strip-shaped outer film 1224 is wound on the outer surface of the metal wire and the inner film 1223, and the metal wires at the intersecting points are not covered by the outer film 1224, that is No outer film 1224 is provided at the intersection. In this way, when the fitting 118 bears against the cross point of the covering film 122 or the position near the cross point, it only acts on the inner film 1223, and does not generate an active force on the outer film 1224, thereby avoiding the inner film 1223 and the outer film. The phenomenon that the layer film 1224 is separated.

Through the cooperation of the inner layer film 1223 and the outer layer film 1224, not only can the support frame 121 and the covering film 122 be reliably attached, but also help to avoid the movement of the inner layer film 1223 and the outer layer film 1224 under the action of the assembly part 118. bit.

In one embodiment, the outer film 1224 is helically wound on the outer surface of the wire and the inner film 1223 to avoid covering the intersection. It can be understood that the arrangement of the outer film 1224 is not limited to being helically wound on the outer surface of the metal wire and the inner film 1223, and any arrangement that can prevent the outer film 1224 from covering the hooks of the metal wire is acceptable. .

Please refer to FIG. 27 , in one embodiment, the outer film 1224 includes two parts, that is, a plurality of first strip-shaped films 1224A and a plurality of second strip-shaped films 1224B, wherein the plurality of first strip-shaped films 1224A are parallel , covering the outer surface of the metal wire and the inner film 1223 at intervals, and a plurality of second strip films 1224B are parallel and at intervals covering the outer surface of the metal wire and the inner film 1223 (the inner film 1223 is omitted in FIG. 27 ) superior. Moreover, the first strip-shaped film 1224A and the second strip-shaped film 1224B intersect, and neither the first strip-shaped film 1224A nor the second strip-shaped film 1224B covers the intersecting crossing points of the metal wires. In this way, the adhesion between the metal wire and the outer film 1224 is more reliable.

Please refer to FIG. 27 and FIG. 28 together. It can be understood that the first strip film 1224A and the second strip film 1224B must be connected under the premise of ensuring that the metal wire and the outer film 1224 are reliably bonded and the intersecting intersections of the covering metal are avoided. The width of can be set reasonably.

It should be noted that, in other embodiments, the outer film 1224 includes a first strip-shaped film 1224A and a second strip-shaped film 1224B, the first strip-shaped film 1224A and the second strip-shaped film 1124B are continuous structures, and The first strip-shaped film 1224A and the second strip-shaped film 1224B intersect, and neither the first strip-shaped film 1224A nor the second strip-shaped film 1224B covers the intersecting intersections of the metal wires.

By reasonably setting the performance of the coating 122 and the assembly parts 118 , it is beneficial to improve the assembly accuracy of the stent delivery system 100 . At the same time, the arrangement of the assembly parts 118 to improve the assembly accuracy can also be applied to the bracket 120 containing the covering film 122 .

The stent transporter 110 is not only suitable for single-layer stents, but also for double-layer stents. Please refer to FIG. 29 , in one embodiment, part of the bracket 120 has a double-layer structure. The stent 120 includes a first tube body 120A and a second tube body 120B. The first tube body 120A is a lumen structure with both ends open, the second tube body 120B is sleeved on the first tube body 120A, and the second tube body 120B At least one end of the first pipe body 120A is fixedly connected to the outer peripheral surface. And, the outer peripheral surface portion of the first pipe body 120A is covered with the second pipe body 120B. Both the tubular body A of the first stent 1 and the second tubular body 120B can be covered stents or bare stents. On the sheath core tube 112, a plurality of fittings 118 are arranged at intervals, and the height h1 of the fittings 118 facing the first tube body 120A and the second tube body 120B in the radial direction is smaller than the height h1 of the fittings 118 facing only the first tube body 120B in the radial direction. The body 120A is opposite to the assembly part 118, but it is still necessary to ensure that the assembly part 118 has a sufficient height h1 to hook with the bracket 120 to produce a limiting effect. This is because the lumen of the outer sheath 113 is an equal-diameter lumen, and when the stent 120 is assembled in the outer sheath 113, since the stent 120 is partially double-layered, the second tubular body 120B must occupy the inner cavity of the outer sheath. There is a certain space in the lumen of 113, when the height h1 of the assembly part 118 opposite to the first tube body 120A and the second tube body 120B in the radial direction is too large, there is a risk of damaging the stent 120 and/or the outer sheath tube 113 .

In one embodiment, when both the first tubular body 120A and the second tubular body 120B are stent-grafts, the height h1 of the assembly part 118 opposite to the first tubular body 120A and the second tubular body 120B in the radial direction satisfies : 0.4×d1−2×d2−t≤h1≤0.8×d1, so that the free end of the assembly part 118 protrudes from the wire of the first tube body 120A, but does not damage the coating.

In one embodiment, when both the first tubular body 120A and the second tubular body 120B are bare stents, the height h1 of the assembly part 118 facing the first tubular body 120A and the second tubular body 120B in the radial direction satisfies: 0.35×d1-2×d2-t≤h1≤0.75×d1, so that the free end of the fitting 118 protrudes from the wire of the first tube body 120A, but the inner wall of the outer sheath tube 113 is not damaged.

In one embodiment, when the second pipe body 120B does not cover both ends of the first pipe body 120A, as shown in FIG. The opposite assembly part 118 can be omitted, and the assembly part 118 is arranged at the proximal end and the distal end of the first tube body 120 , which can also realize the limitation of the bracket 120 .

The stent delivery system 100 improves the assembly accuracy from the source, which is beneficial to avoid affecting the intraoperative release accuracy due to poor assembly accuracy. The release process of the stent 120 will be described below with reference to FIGS. 30a to 30d.

After the stent 120 is delivered to the lesion by the stent delivery device 110, the stent 120 is still located in the lumen of the outer sheath 113, as shown in FIG. Keep the sheath core tube 112 still, move the outer sheath tube 113 axially away from the guide head 111, the bracket 120 is in contact with the inner wall of the outer sheath tube 113, and under the frictional force of the outer sheath tube 113, the bracket 120 moves along with the inner wall of the outer sheath tube 113 The outer sheath 113 tends to move away from the guide head 111 together. If the stent 120 is significantly displaced in the direction away from the guide head 111, the stent 120 will be squeezed in the inner cavity of the outer sheath 113. In severe cases The accumulation will be generated, which will reduce the release accuracy, for example, the position of the stent 120 will be shifted or the shape of the stent 120 will be twisted. And, the position offset is released. As shown in Figure 30b, but because the assembly part 118 is provided, the assembly part 118 remains hooked and connected with the bracket 120, and during the movement of the outer sheath tube 113, the bracket 120 can resist the friction of the outer sheath tube 113, so the bracket 120 and the bracket 120 The sheath core tube 112 remains relatively stationary. Please refer to Figures 30a to 30e together, since a plurality of assembly parts 118 are arranged at intervals along the axial direction of the sheath core tube 112, as the outer sheath tube 113 gradually moves away from the guide head 111, the stent 120 is gradually released, but At least part of the part located in the lumen of the outer sheath tube 113 is hooked with the assembly part 118, which can effectively prevent the stent 120 from shifting, thereby improving the release accuracy. Due to the restoring force of the stent 120 itself, when the stent 120 is bound by the outer sheath tube 113 and disappears, the stent 120 will automatically bounce off and adhere to the inner wall of the tissue, thereby completing the release.

In order to ensure that the stent 120 is always limited by the assembly part 118 during the whole release process and remains relatively fixed with the sheath core tube 112 throughout the whole process, in one embodiment, the assembly part 118 farthest from the guide head 111 in the axial direction and the stent The metal mesh of 120 that is farthest from the guide head 111 in the axial direction is hooked or the crest or trough is hooked, that is, at least one fitting 118 is located at the proximal end of the bracket 120 .

Since the stent 120 is gradually released, during the release process, when the ratio of the axial length of the released part of the stent 120 to the axial length of the part of the stent 120 located in the outer sheath 113 is large, the stent 120 It will bounce off automatically, and the most distal end of the bracket 120 (that is, the part to be released first) at least contacts the inner wall of the tissue to produce a certain position-limiting effect. Therefore, even if the assembly part 118 farthest from the guide head 111 in the axial direction is somewhat away from the proximal end of the stent 120 , it can ensure that the stent 120 and the sheath core tube 112 are prevented from sliding relative to each other during the whole release process.

In one embodiment, when the stent 120 is radially crimped on the sheath core tube 112 (the state in which the stent 120 is hooked with all the fittings 118), the axis of the proximal end surface of the fitting 118 located at the most end and the stent 120 The ratio of the axial distance to the axial length of the bracket 120 is not greater than 1/3.

In one embodiment, the plurality of fittings 118 near the distal end are closely spaced to facilitate release. This is because in the release process, the release force is the largest at the beginning of the release, which is most likely to cause the distal end of the bracket 120 to move and stack, so that it cannot be released. A good restriction on the movement of the bracket 120 avoids failure to release or reduces the difficulty of release.

In one embodiment, when the stent 120 is radially crimped on the sheath core tube 112 (the state in which the stent 120 is hooked with all the fittings 118), the farthest fitting 118 and the distal end surface of the stent 120 The ratio of the axial distance of the stent 120 to the axial length of the stent 120 is not greater than 1/3, which is beneficial to avoid proximal stacking during the assembly process.

Conventional stent deliverers are often unable to retrieve the stent after the stent is partially released. Therefore, once the stent is twisted after release or cannot be released after part of it is released, it cannot be remedied. In this case, the graft can only be removed by surgery, which may bring danger to the patient. Or, when the release position is inaccurate, it is also difficult to adjust the release position by recycling, which will affect the therapeutic effect. The stent delivery system 100 of the present disclosure can achieve recovery, thereby avoiding the above-mentioned problems.

It can be understood that the order in which the stent 120 is retrieved is reverse to the order in which it is released. First, please refer to FIG. 30 e , when a part of the stent 120 is released and found to be abnormal and needs to be recovered, the sheath core tube 112 is kept still, and the outer sheath tube 113 is moved toward the direction close to the guide head 111 . During the movement of the outer sheath tube 113 toward the guide head 111 , friction occurs between the inner wall of the outer sheath tube 113 and the outer wall of the bracket 120 , thus exerting a pushing force toward the guide head 111 on the bracket 120 . Therefore, the stent 120 has a tendency to move together with the outer sheath tube 113 , that is, to move relative to the sheath core tube 112 . But because the part of the stent 120 located in the lumen of the outer sheath tube 113 is still hooked to the assembly part 118, the assembly part 118 will give the stent 120 an active force against movement, thereby preventing the movement of the stent 120. Therefore, the recovery of the stent 120 can be realized by pushing the outer sheath tube 113 toward the direction close to the guide head 111 . The state changes of the recovery process are shown in Fig. 30e, Fig. 30d, Fig. 30c, Fig. 30b, and Fig. 30a in turn. When the outer sheath tube 113 advances toward the direction of the guide head 111, the part outside the outer sheath tube 113 and the mesh of the stent 120 The cells gradually approach the fitting 118 until the fitting 118 penetrates the grid. The outer sheath tube 113 continues to advance toward the direction of the guide head 111 , and the assembly part 118 and the stent 120 are taken into the outer sheath tube 113 to realize recovery of the stent 120 . In the traditional stent delivery device, since there are no assembly parts, if a part of the stent 120 is released and the stent 120 is recovered, the stent 120 will move along with the outer sheath 113 during the operation, making it difficult to recover.

By rationally designing the structure and quantity of the assembly parts 118 , during the assembly process, the assembly parts 118 can provide a certain and reliable anti-displacement force for the bracket 200 without being pulled apart, so as to realize the recovery of the bracket 120 . And, as mentioned above, by rationally setting the coating of the assembly part 118 and the bracket 120, the assembly part 118 will not break the coating 122 or cause damage to the coating 122 during the recycling process. Therefore, the bracket can be recycled After 120, adjust the position and continue to release the bracket 120.

Therefore, with the assembly parts 118 set up reasonably, the stent delivery system 120 not only improves the accuracy from the source of assembly, but also improves the accuracy during the release process, which is conducive to the smooth progress of the interventional operation and ensures the curative effect. Moreover, it can also be recycled when an unexpected situation occurs, which is safe and reliable.

It should be noted that, on the premise that the fitting 118 can be reliably hooked to the bracket 120 and the fitting 118 does not damage the membrane 122 and/or the outer sheath 113, the fitting 118 is not limited to the specific structure described above. , can be other structures. For example, referring to FIG. 31 , a plurality of assembly parts 118 are connected by connecting parts 119 to form an assembly assembly 130 . When assembling, the assembly component 130 is directly installed on the sheath core tube 112 .

Please refer to FIG. 32 and FIG. 33 together. The connecting piece 119 is roughly rod-shaped, and can be a flat rod or an arc-shaped rod. Any two adjacent assembly parts 118 can be connected by at least one connecting piece 119 . Both ends of each connecting piece 119 are respectively connected to the bases 1182 of two adjacent assembly pieces 118 . The number of fittings 118 of each fitting assembly 130 can be reasonably set according to the length of the bracket 120 . The number of assembly components 130 on each rack conveyor 110 can be reasonably set based on the length of the rack 120 and the number of assembly parts 118 of each assembly assembly 130 . The assembly component 130 formed by connecting multiple assembly parts 118 with the connecting part 119 is relatively convenient to prepare. Due to the small size of each assembly part 118 , manufacturing a single assembly part 118 requires a higher mold to meet the precision requirements. The size of the assembly component 130 is relatively large, the requirements for the mold are relatively low, and it can be injection molded at one time.

The number and location of the connecting parts 119 between two adjacent assembly parts 118 may be the same or different. As shown in FIG. 31 , in one embodiment, two adjacent assembly parts 118 are connected by two connecting parts 119 arranged at intervals along the circumferential direction of the sheath-core tube 112 . Referring to FIG. 32 and FIG. 33 , for the non-end fitting 118 , the plane formed by the two connecting pieces 119 at its distal end and the plane formed by the two connecting pieces 119 at its proximal end are perpendicular. Such arranging of the connecting member 119 is beneficial to ensure that the flexibility of the stent transporter 110 in any angular direction is consistent, and it is beneficial to pass through complicated and curved paths.

The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, should be considered as within the scope of this specification.

The above-mentioned embodiments only express several implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but should not be construed as limiting the patent scope of the invention. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (13)

1. The bracket conveying system comprises a bracket and a bracket conveyor, and is characterized in that the bracket conveyor comprises a sheath core pipe, an outer sheath pipe and an assembly part, wherein the outer sheath pipe is sleeved on the sheath core pipe in an axially slidable manner, a containing cavity for containing the bracket is formed between the inner wall of the outer sheath pipe and the outer wall of the sheath core pipe, the assembly part is provided with a fixed end and a free end opposite to the fixed end, the fixed end is connected with the sheath core pipe, and when the bracket is radially pressed on the sheath core pipe, the free end is hooked with the bracket to limit the bracket; the assembly member is inclined relative to the longitudinal central axis of the sheath core tube, and the assembly member is a plurality of assembly members;

Wherein a free end of the fitting partially distally located is closer to the distal end than the fixed end and a free end of the fitting partially proximally located is closer to the proximal end than the fixed end;

the fitting has elasticity, the fixed end is a rigid portion, and the free end is a flexible portion.

2. The stent delivery system of claim 1, wherein the stent is a bare stent, the inner diameter of the outer sheath is d1, the height of the fitting is h1, the stent comprises a support skeleton formed from a woven wire or cut from a metal tube, the wire diameter of the wire or the wall thickness of the support skeleton is d2, the d1, h1, and d2 satisfying: 0.4Xd1-2 Xd2.ltoreq.h1.ltoreq.0.85Xd1.

3. The stent delivery system of claim 1, wherein the stent is a bare stent, the inner diameter of the outer sheath is d1, the height of the fitting is h1, the d1 and h1 satisfy: h1 is more than or equal to 0.45×d1 and less than or equal to 0.5mm and is less than or equal to 0.55×d1+0.5mm.

4. The stent delivery system of claim 1, wherein the inner diameter of the sheath tube is d1, the height of the fitting is h1, the stent comprises a support framework and a coating film coated on the support framework, the support framework is formed by braiding wires or cutting wires, the wire diameter of the wires or the wall thickness of the support framework is d2, the thickness of the coating film is t, and the d1, h1, d2 and t satisfy: 0.35 Xd1-2 Xd2-t.ltoreq.h1.ltoreq.0.85 Xd1.

5. The stent delivery system of claim 4, wherein d1, h1, d2, and t satisfy: 0.35 Xd1-2 Xd2-t.ltoreq.h1.ltoreq.0.7 Xd1.

6. The stent delivery system of claim 1, wherein the cross-sectional area of the fitting is S1, the stent comprises a support framework comprising a plurality of closed loops of mesh, the area of a single mesh being S2 in a naturally deployed state, the S1 and S2 satisfying: s1 is more than or equal to 0.001×S2 and less than or equal to 0.2×S2.

7. The stent delivery system of claim 1, wherein the cross-sectional area of the fitting is S1, the stent comprises a support framework comprising a plurality of undulating ring structures comprising peaks and valleys, the peaks or valleys having a radius R1, the S1 and R1 satisfying: 0.05X1×R1×pi.s1.ltoreq.R1×R1×pi.

8. The stent delivery system of claim 1, wherein the stent comprises a support scaffold and a coating over the support scaffold, the coating having an elongation of greater than or equal to 95% and less than or equal to 300%.

9. The stent delivery system of claim 1, wherein the stent comprises a support framework and a coating coated on the support framework, wherein the coating has a breaking strength that: 0.5 The N/mm is less than or equal to 15.0N/mm of breaking strength.

10. The stent delivery system of claim 1, wherein the stent comprises a support framework and a coating over the support framework, the coating having a thickness t, the fitting having a height h1, the t and h1 satisfying: t/h1 is more than or equal to 0.010 and less than or equal to 0.500.

11. The stent delivery system of claim 1, wherein in a natural state, the stent has an outer diameter D1 and the outer sheath has an inner diameter D1, the D1 and D1 satisfying: D1-D1)/D1 is more than or equal to 40% and less than or equal to 85%.

12. The stent delivery system of claim 1, wherein a ratio of an axial distance of a fitting located at a proximal end to a proximal end face of the stent to an axial length of the stent is no greater than 1/3 when the stent is radially crimped onto the sheath tube.

13. The stent delivery system according to claim 1, wherein the stent comprises a first tube body and a second tube body, the second tube body is fitted over the first tube body, at least one end of the second tube body is connected to an outer peripheral surface of the first tube body, the fitting is plural, at least one fitting is hooked to a portion of the first tube body covered by the second tube body, at least one fitting is hooked to a portion of the first tube body not covered by the second tube body, and a height of a fitting hooked to a portion of the first tube body covered by the second tube body is smaller than a height of a fitting hooked to a portion of the first tube body not covered by the second tube body.